The tribunal yesterday heard dramatic new evidence which appears to provide independent corroboration of Mr James Gogarty's allegations about payments to Mr Ray Burke and which could prove a body-blow to the version of events put forward by the Murphy group.
On a day of high drama and strained emotions, two tribunal lawyers put forward - from the witness-box - a version of events that appears to show that senior managers in Murphys knew all along about the payment to Mr Burke, that the money was given in return for planning favours, and that Mr Gogarty was not centrally involved in the transaction.
Their accounts were based on interviews with Mr Gay Grehan, a director of Joseph Murphy Structural Engineering, from which a draft statement was drawn up by the tribunal.
However, Mr Grehan subsequently declined to sign this statement and later submitted through his solicitor a vastly differing version of events.
The result yesterday was an extraordinary standoff between tribunal lawyers and Mr Garret Cooney SC, for JMSE, who battled all day to have the draft statement ruled out. After losing two decisions by the chairman, and protesting vehemently about the conduct of tribunal lawyers, Mr Cooney resolved to take his grievance to the professional practices committee of the Bar Council.
Only three months ago, Mr Cooney took an earlier complaint against the chairman to the Bar Council, but this was resolved after mediation.
Yesterday's revelations raise further questions for the Tanaiste, Ms Harney, to answer.
She said in evidence last week that Mr Grehan told her in 1997 that JMSE had paid £30,000 to Mr Burke. If his draft statement is to be believed, Mr Grehan was given this information in 1989/90 by a senior colleague, Mr John Maher.
Ms Harney's statement to the tribunal also details her discussions with her Progressive Democrat colleague, Mr Michael McDowell, who had been contacted by Mr Gogarty with his allegations.
She was therefore uniquely placed in public life, having been given clear information from two independent sources alleging that Mr Burke was receiving corrupt payments. Yet she did nothing and said nothing when Mr Bertie Ahern assured her Mr Burke was fit to be appointed to the Cabinet in June 1997.
And how could Mr Joseph Murphy jnr have told Fianna Fail then that JMSE had not paid money when senior executives of the company knew precise details of this seven years earlier?
Mr Grehan and his wife, Dr Mary Grehan, who was present for both meetings with the tribunal lawyers, will now be called to give evidence on both statements on Monday. This is likely to cause some embarrassment for the PDs, as Dr Grehan is standing as a party candidate in the local elections next month in Co Louth.
In the draft statement that Mr Grehan refused to sign, he is recorded as saying that he first found out about the Burke payments five or six months after June 1989. The money was collected by Mr Frank Reynolds, a senior JMSE executive, and an accountant, Mr Tim O'Keeffe.
The draft statement says the payment was never discussed at board level. Mr Reynolds met Mr Michael Bailey, the developer who bought the north Dublin lands sold by Murphys, "a fair bit". Mr Gogarty's role in the matter was never queried in 1989.
The draft statement says Mr Grehan had difficulties with the 1988 accounts, and was pressurised to sign them. This echoes Mr Gogarty's account.
It was last November that Mr Grehan first met tribunal lawyers Mr Patrick Hanratty SC and Mr Des O'Neill SC in his home in Dundalk. Mr Hanratty took notes and drew up a draft statement, which he showed to Mr Grehan at a second meeting just before Christmas.
According to Mr Hanratty, Mr Grehan agreed with the statement except for one matter, which he wanted time to consider. The following day, in a phone conversation, he said he wished to consult a solicitor.
Mr Hanratty said Mr Grehan was nervous about being called as a witness and preferred not be involved. In January, however, Mr Grehan's solicitor filed a sworn statement which, according to the tribunal, contains "significant differences/omissions" from the draft.
In his sworn statement, Mr Grehan dates his knowledge of the Burke payment not from 1989/90, but from late 1996, when allegations were beginning to appear in the newspapers anyway. He attributes some of his knowledge to Mr Gogarty rather than Mr Maher, and he makes no mention of a matching £30,000 being paid to Mr Burke by Mr Bailey.
What were given as statements of fact in the draft, such as that Mr Gogarty was Mr Joseph Murphy snr's "right-hand man" or that he had Mr Murphy's "complete confidence", were now said to be just assumptions.
He says his understanding of events was based on "rumour and hearsay".
With Mr Hanratty and Mr O'Neill sticking by the accuracy of their draft, Mr Grehan will have a hard job on Monday convincing Mr Justice Flood that two experienced barristers could have erred so much.
Earlier, Mr Cooney launched the kind of blistering attack on his colleagues on the tribunal legal team that will have the Law Library buzzing for days. Accusing Mr Hanratty and Mr O'Neill of "dubious ethical standards", he suggested they were coaching a witness (Mr Grehan) by supplying him with information from other statements.
Mr Hanratty said it was all "a litany of allegation of professional misconduct, which I utterly reject", and "unworthy" of Mr Cooney to "stoop so low".
Because of the allegations of impropriety, Mr Justice Flood put the two lawyers in the witness-box so they could clear their names. It was one more extraordinary sight in an extraordinary tribunal.